An effective, safe and easily reversible male contraceptive with universal acceptability remains an elusive goal. Although a variety of approaches for achieving male contraception have been tried, no single mode of male contraception is without its immediate drawbacks for efficacy or compliance. Even seemingly simple interventions have not proven to be widely acceptable. For example, surgical or non-surgical vasectomy, methods that interrupt sperm transport in the male reproductive tract, are not without their complications or long-term risk. More complex approaches, such as regimens for the hormonal control of male fertility, have also not been fully satisfactory. Such methods have focused on the suppression of spermatogenesis to the point of azoospermia, a goal that has been difficult to achieve. The use of the immune response to block contraception has been an important front in efforts to develop more sophisticated contraceptive systems. Unfortunately, such approaches have thus far failed, as male autoimmunity against sperm does not suppress sperm production in men; this is known because such autoimmunity can occur after vasectomy. Thus, inhibiting sperm fertilizing-ability without affecting the hormonal balance in either the male or female remains an important goal in the field of reproductive biology. The present invention achieves this goal.